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irqchip/gic-v3-its: Move pending table allocation to init time 

Pending tables for the redistributors are currently allocated
one at a time as each CPU boots. This is causing some grief
for Linux/RT (allocation from within a CPU hotplug notifier is
frown upon).

Let's move this allocation to take place at init time, when we
only have a single CPU. It means we're allocating memory for CPUs
that are not online yet, but most system will boot all of their
CPUs anyway, so that's not completely wasted.

Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Tested-by: Lei Zhang <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
4.20.x+fslc
Marc Zyngier 2018-07-27 13:38:54 +01:00
parent 053be4854f
commit 11e37d357f
2 changed files with 54 additions and 29 deletions
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82
drivers/irqchip/irq-gic-v3-its.c
View File

@ -173,6 +173,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock);
static DEFINE_IDA(its_vpeid_ida);
#define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
#define gic_data_rdist_cpu(cpu) (per_cpu_ptr(gic_rdists->rdist, cpu))
#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
#define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() + SZ_128K)
@ -1625,7 +1626,7 @@ static void its_free_prop_table(struct page *prop_page)
get_order(LPI_PROPBASE_SZ));
}
static int __init its_alloc_lpi_tables(void)
static int __init its_setup_lpi_prop_table(void)
{
phys_addr_t paddr;
@ -1944,29 +1945,46 @@ static void its_free_pending_table(struct page *pt)
free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ));
}
static int __init allocate_lpi_tables(void)
{
int err, cpu;
err = its_setup_lpi_prop_table();
if (err)
return err;
/*
* We allocate all the pending tables anyway, as we may have a
* mix of RDs that have had LPIs enabled, and some that
* don't. We'll free the unused ones as each CPU comes online.
*/
for_each_possible_cpu(cpu) {
struct page *pend_page;
pend_page = its_allocate_pending_table(GFP_NOWAIT);
if (!pend_page) {
pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu);
return -ENOMEM;
}
gic_data_rdist_cpu(cpu)->pend_page = pend_page;
}
return 0;
}
static void its_cpu_init_lpis(void)
{
void __iomem *rbase = gic_data_rdist_rd_base();
struct page *pend_page;
phys_addr_t paddr;
u64 val, tmp;
/* If we didn't allocate the pending table yet, do it now */
if (gic_data_rdist()->lpi_enabled)
return;
pend_page = gic_data_rdist()->pend_page;
if (!pend_page) {
phys_addr_t paddr;
pend_page = its_allocate_pending_table(GFP_NOWAIT);
if (!pend_page) {
pr_err("Failed to allocate PENDBASE for CPU%d\n",
smp_processor_id());
return;
}
paddr = page_to_phys(pend_page);
pr_info("CPU%d: using LPI pending table @%pa\n",
smp_processor_id(), &paddr);
gic_data_rdist()->pend_page = pend_page;
}
paddr = page_to_phys(pend_page);
/* set PROPBASE */
val = (page_to_phys(gic_rdists->prop_page) |
@ -2019,6 +2037,10 @@ static void its_cpu_init_lpis(void)
/* Make sure the GIC has seen the above */
dsb(sy);
gic_data_rdist()->lpi_enabled = true;
pr_info("GICv3: CPU%d: using LPI pending table @%pa\n",
smp_processor_id(),
&paddr);
}
static void its_cpu_init_collection(struct its_node *its)
@ -3497,16 +3519,6 @@ static int redist_disable_lpis(void)
u64 timeout = USEC_PER_SEC;
u64 val;
/*
* If coming via a CPU hotplug event, we don't need to disable
* LPIs before trying to re-enable them. They are already
* configured and all is well in the world. Detect this case
* by checking the allocation of the pending table for the
* current CPU.
*/
if (gic_data_rdist()->pend_page)
return 0;
if (!gic_rdists_supports_plpis()) {
pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
return -ENXIO;
@ -3516,7 +3528,18 @@ static int redist_disable_lpis(void)
if (!(val & GICR_CTLR_ENABLE_LPIS))
return 0;
pr_warn("CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
/*
* If coming via a CPU hotplug event, we don't need to disable
* LPIs before trying to re-enable them. They are already
* configured and all is well in the world.
*/
if (gic_data_rdist()->lpi_enabled)
return 0;
/*
* From that point on, we only try to do some damage control.
*/
pr_warn("GICv3: CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
smp_processor_id());
add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
@ -3772,7 +3795,8 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
}
gic_rdists = rdists;
err = its_alloc_lpi_tables();
err = allocate_lpi_tables();
if (err)
return err;

1
include/linux/irqchip/arm-gic-v3.h
View File

@ -585,6 +585,7 @@ struct rdists {
void __iomem *rd_base;
struct page *pend_page;
phys_addr_t phys_base;
bool lpi_enabled;
} __percpu *rdist;
struct page *prop_page;
u64 flags;